In order to impart modification effects and functional effects to a skin surface layer and a skin stratum corneum, liquid materials, ointments, cream preparations, tape preparations, patch preparations, poultice preparations, and the like containing medicinal ingredients have been conventionally used. Such preparations are intended to exhibit the effects by allowing the medicinal ingredients to penetrate into skin through their application or attachment to a skin surface. However, the above-mentioned conventional preparations cannot achieve sufficient effect, because simply applying the preparations to the skin brings about easy disappearance and loss of the medicinal ingredients due to a perspiration function of the skin, contact of the skin with the outside, and the like. Moreover, since the skin has a barrier function for preventing entry of foreign matters into a body, it is difficult to allow the medicinal ingredients to penetrate into the skin only through their application or attachment.
Recently, as a method for solving these drawbacks and surely supplying the medicinal ingredients into the skin, microneedles have been developed, and research thereof has been conducted. The microneedles are microscopic needles with a length of less than 1 mm (Patent Document 1). When the microneedles are made of material which is easily dissolved to disappear in vivo, the inserted microneedles are dissolved in the skin and then absorbed to disappear (Patent Document 2). Therefore, if the medicinal ingredients are contained in the microneedles beforehand, the medicinal ingredients can be supplied to a particular place in the skin. A microneedle array is formed by arranging a number of such microneedles on a substrate, and it has been largely expected on practical uses because a delivery amount can be increased in proportion to the number of the needles (Patent Documents 2 to 4, Non-patent Document 1). A microneedle patch is an easily usable product formed by supplementing the microneedle array with an adhesive tape and the like for sticking the microneedle array on the skin.
Because the microneedles have generally a length of shorter than 1 mm and a diameter of around 0.1 mm, they do not cause pain and bleeding at their insertion. An insert point closes quickly and does not leave any trace. As a result, the microneedles are recognized as an excellent method for delivering the particular medicinal ingredients to the particular point of the skin. The microneedles have attracted attention by having application as cosmetics, for example delivery of skin active components such as hyaluronic acid to the skin surface, concealment of lentigines and birthmarks, and the like, in addition to medical application such as delivery of vaccine.
An early microneedle comprised around 100 microneedles on a solid substrate with an area of around 1 cm2. However, based on a recent increased demand for improving a wide part of a face at a time, a microneedle array comprising the microneedles on a softened substrate have been developed in order to fit the array to a non-planar face.
Suitable containers are necessary for providing the microneedle arrays to consumers in the market. Since the microneedle array has a needle portion and it is necessary to protect the needle portion during transport, sale or preservation, containers for patches, such as tapes, which are widely used conventionally (Patent Documents 5 and 6), cannot be used as they are. In addition, containers for solid substrates (Patent Documents 7 to 9) cannot be used for the microneedle array with a soft substrate.